In some applications and aspects of semiconductor technology, minimizing the size and weight of semiconductor devices is desirable. For example, aspects of semiconductor technology relate to minimizing the size of embedded components. System On Chip (SOC) technology may integrate a plurality of components into one chip. System In Package (SIP) technology may integrate a plurality of devices or chips into one package.
SIP technology may incorporate (e.g. mount) a plurality of silicon chips vertically or horizontally in one package. SIP technology may be an extension of a Multi-Chip Module (MCM) concept. In some MCM configurations, integration of semiconductor devices may be implemented by horizontal mounting in a package. In some SIP configurations, chips may be stacked vertically.
As illustrated in example FIG. 3, three manufactured devices may be vertically stacked, with wafers of the devices connected using a deep via. As illustrated in example FIG. 4, since devices are horizontally connected in a SOC, the size of a SOC semiconductor device may be larger than a SIP semiconductor device. In SIP technology, a number of metal wirings for electrical connections may be provided between upper and lower chips. Metal wirings may be formed of a metal material (e.g. Tungsten (W), Copper (Cu), and Aluminum (Al)).
However, if metal wirings are formed of Cu, Cu atoms may diffused into insulating films and may cause leakage current. Cu may also be diffused into individual components (e.g. transistors), resulting in Cu atoms being impurities, because Cu atoms may have a relatively high diffusivity in insulating films and silicon films. Accordingly, in order to form metal wirings of Cu for metal plugs and/or upper wirings in an SIP semiconductor device, it may be necessary to form a diffusion barrier film which prevents diffusion of Cu atoms into insulating films.
Diffusion barrier films may be formed using Physical Vapor Deposition (PVD), which may cause relatively low quality step coverage. Accordingly, using PVD may not be possible in some applications for forming a diffusion barrier film. It may be prohibitive to form a diffusion barrier film (e.g. a titanium nitride (TiN) film) using Metal-Organic Chemical Vapor Deposition (MOCVD), as the materials often used for MOCVD can not be used as diffusion barriers for Cu, as it may diminish reliability of a semiconductor device due to relatively high temperature formation processes.